When the Vegas oddsmakers put out betting lines on the MLS playoffs last week, they listed the Galaxy as the favorites to win the Western Conference and advance to their first MLS Cup final in a decade.

If that raised a few eyebrows, given the way the team played in its playoff opener Saturday, maybe the sportsbooks aren’t giving the team enough credit. Because with Dejan Joveljic and Riqui Puig each scoring two goals and John Nelson adding his first MLS score, the Galaxy blew out the Colorado Rapids 5-0 at Dignity Health Sports Park in a game that was far more one-sided than the score.

The score matched the largest margin of victory in a playoff game in franchise history, one last achieved in the first round against Real Salt Lake in 2014. That was also the last time the Galaxy played in the MLS Cup final. And Saturday’s match was the most lopsided loss for the Rapids in more than two years.

“It was a very clean performance. Probably one of the best I can remember,” Galaxy coach Greg Vanney said. “And at a good time.”

The Galaxy go to suburban Denver for the second game of the best-of-three series Friday needing another win to advance to the conference semifinals. A loss would force a third game at Dignity Health Sports Park on Nov. 9.

Neither outcome is ideal for the Galaxy, given the bizarre MLS playoff schedule.

Sweeping the first two games would send the Galaxy to the conference semifinals, but with the playoffs pausing for the November international break, the team’s next game wouldn’t be until Nov. 23 at the earliest, a 22-day pause that threatens to rob the team of its rhythm.

A loss, meanwhile, would force a winner-take-all game at home with the Galaxy’s season on the line. Vanney said he’s not about to overthink it.

“In the best of three, you take this win and now we’ve got two games to win one to get to the next round,” he said.

Given the way the Galaxy dominated, Saturday’s result may be worth a little more in ways that weren’t reflected on the score sheet.

“Now we have all the momentum,” Nelson said. “The job’s not done. We keep going. [But] we set the tone. We set the intensity.”

The Galaxy did that from the start, attacking from the opening whistle and finally getting rewarded for their aggression in the 32nd minute when Joveljic, cradling Colorado defender Reggie Cannon with his chest, got his forehead on Puig’s outswinging corner kick and looped a soft header inside the right post.

It was the 70th goal of the season for the Galaxy but just the third off a corner, which has been a weakness for them.

Outside backs Miki Yamane and Nelson teamed to double the lead seven minutes into the second half, with Yamane threading a ball through the box for a wide-open Nelson, who settled it with one foot then sent a right-footed shot into the top right corner for the first goal of his six-year career.

“As soon as Miki played it, I felt in my head, if this ball goes through, I’m scoring this,” Nelson said. “And it got through. I was composed, I was calm. There was no doubt.”

Two minutes later, Puig, who was all over the field, made it 3-0 after Joveljic deflected a Nelson pass in front of him at the top of the box, setting up an easy, right-footed finish. Joveljic and Puig then closed out the scoring with Joveljic running on to the rebound of a Gabriel Pec shot, dribbling across the top of the box to create space, then beating U.S. national team goalkeeper Zack Steffen cleanly with his left foot in the 75th minute for his team-leading 17th goal. Puig bagged his second goal of the night — and 15th of the season — 12 minutes later.

Almost as impressive as the offense was the defense, which didn’t give up a shot on goal, allowing keeper John McCarthy to record his seventh clean sheet of the season. A big reason for that was Colorado rarely had the ball, with the Galaxy maintaining possession for 60 of the 90 minutes, which was a big part of the game plan.

“I don’t really remember having to defend one versus one, we were on the ball so much,” Nelson said. “This whole week was, as soon as we lose [the ball], counter press. We’re up in their face. We’re ready. We’re fouling them. We’re winning the ball back.

“It was relentless. And that’s what we need to do, be relentless.”

Odds are if they continue playing that way, they’ll remain a good bet to return to the MLS Cup final.